Previous work on enhancement of hydrogen production via biological process were attempted using molecular technique for the modification of microbial biohydrogen pathway with suppression of lactic and succinic acid biogenic path (Yukawa et al., 2010: U.S. Pat. No. 7,816,109B2) or exploration of organic waste containing H2 producing microbes and an activated carbon based carrier combination to adhere and proliferate more biomass for enhance H2 production (Lin et al., 2007: U.S. Pat. No. 7,232,669 B1) or membrane based two stage biohydrogen production from organic waste using dark and photo-linked fermentation (Nirmalakhandan et al., 2013; U.S. Pat. No. 8,343,749 B2) or exploitation of in vitro enzymatic process in water solution that effectively converts low cost feed-stocks into high yield biohydrogen (Zhang et al., 2012; U.S. Pat. No. 8,211,681 B2) and so on. None of the patent has been filed regarding supplementation of organic acids (lactic, acetic and butyric acids) to inhibit their production via feed-back inhibition or other related mechanism for enhancement of biohydrogen production from glucose or reducing sugars from any organic waste. However, Kim et al., (2012) have been reported lactic acid addition enhanced biohydrogen yield (from 1.41-1.72 mol/mol-Glc) moderately from glucose in continuous fermentation operation. Baghchehsaraee et al. (2009) reported that more hydrogen was produced using a mixed substrate with starch and lactic acid.
Masumoto and Nishimura (2007) and Wu et al., (2012) found that mixed substrate of acetic acid and lactic acid enhanced hydrogen production (without glucose). However these processes have utilized higher lactic acid concentration compares to current study and glucose was lacking in studies of Masumoto and Nishimura (2007) and Wu et al., (2012). Moreover these processes were lacking the addition of acetic and butyric acids along with lactic acid hence processes were not turned into significant enhancement in biohydrogen production. Combination of acetic and butyric acid with lactic acid was important which has resulted into significant enhancement of biohydrogen yield (max 4.5 mol/mol-Glc) from glucose in the current study.